Hydraulic jack



Sept. 28, 1943. J. s. RQTHERY 2,330,518

HYDRAULIC JACKS FiledOpt. 28, 1941 2 Sheets-Sheet l Jude/1Z7;

Ei/LEJ 5"- Sept. 28, 1943. J. s. ROTHERY 2,330,513

HYDRAULIC JAGKS I Filed 001:. 28, 1941 2 Sheets-Sheet 2 ing for use withhydraulic rams. V n V I According to one feature of the 1nvention=.-the

ranged atfdifiering heightsin the slee Patented Sept. 28, 1943 I nxnmmmemen Y n v James Stewart Bowery, inqrqgnnglarrd 5' I i Application(jctober 2s, mus el Ni}. MEBQL;

. InGrea't Britain June 24,;1941'1 awnin (01. mean; p e I This inventionrelates to means'f or locking: the extended ram of anhydraulic jack.against unintentional collapse which might occur owing to small leakageor other reason and to apackram of: an hydraulic jack is provided with anumber of. superposedvholesthrough lit,,l'preferably in verticalalignment, andiarioundlthelram on the. head of the jack frame orlstructure or "of. the cylinder is a rotatable' sleevel'iaving it aplurality ofholes preferably impairs; the two holes breach pair beingdiametrically opposite e'achother andthe pairs oi holesfar- M 0 that" towhatever'height the ram may beli edtlie' sleeve can'be rotatedso-as-to'bring ohe "of the pairs of holes iii-itopposite"ornearlyopposit to, i. e., substantially into coincidence with,a hole intl'ie ram aiter' which apin, say on achain, is inserted from"one side or the sleeve througlr the hole therein and through thehole inthe ram and the corresponding hole on" the. other side of the sleeve.

It will be: seen from theabovethat whenthe: ram" has' beenz'extended'tothe desiredheightthe sleeveis rotated uhtil thepin can-he pushed"throughthepair of holes coincidin'gwith ahele" in the ra In-which-isthen locked and any drep will not exceed,/at'the most;the-vertical-distance; between the centres of one pair: of holes in thesleeve. A secondary sleeve tor-other device) screwed inside or outsidethe main sleeve could.

be arranged-totake up this "p1ayif desired but such fine adjustment isnot usually required.

Sufficient adjustment. may alsobe obtainedbyv having thetholeselongated, the line of lelong'a tion rising slightly so rthatfafractional turn "of. the sleeve gives the required ad ustment;,

The diametral. holes in. the. .ramj prleclude the. satisfacto provisionof a. packingjgl'aridf'at the top, of the cylinderfand in' orider toprevent" the escape of working liquidthat? leaks past 1th? cup leatheror like normal ram packii'igfafsaietyf seal has been devised andapplied} to -the ram above the saidcup leather or the like inacjcordanee'fwith'a" furtheniea'ture of the-"inv'e rltion=;a In order to"prevent the jack being raised ihei yond a predetermined heightthecylinder has-a vent-or an exhaust valve which, when comm-unieatingiwiththefpres'sure chamber of the jackowing to the jackbeingraised tothesaid'hei'g ht; allows the working liquidto-return tothe rese1 vo'i-r.Such-en arrangement is diS'elbseddintlie specification of niy- U. S.Patent N01 to eachother; and around the ramand ,resting Accordingto; astill furtherv feature oft-the invention, however, the; saidyalve is ofnon return type whereby liquid is prevented: from; returning to'thecylinder when-thejack is lowered and-escaping by Way of the unpacked topof:- the cylinder; r

The safety seal and the; vent with'z-the non return valve may be usedwith other: types of hydraulic jacks, for; example, jacks having ex--ternally screw-threaded rams on" which isa nut which can be setlongitudinally of the ram'to, sustainit bythrusting against the top 0fthe jack. 1

Therinvention will now be described with referer rce to the accompanyingdrawings wherein: Fig; 1 .isa perspective view 1 of the jack, the

ram being lowered:

fig; 2C isaside el'evation; partly. in section,

showing tl'ie'top" of: the jack cylinder, the .rotat-v ahlesleeveand'theilower part of the ram with a saiety seal. v I y i Fig; 2 'ls a.det'ailoi 'a-modifiedformoi safety seal.

Fig.1 3 is a purposes: and

Fig. 4 is :a fragmentary view of a jack incorporating a; sleevewith-elongated holes.-

The-jackshownin- Fig. 1 comprises-thetubular tripod I from the peak ofwhich-the ram cylinder 2 depends, the legs beingflbraced toe and intothe 'reservoir-toallow the ram to sink The? jackias described so far issubstantially as described in my;said- U; S. patent specificationrAceordingqto one feature of the present'invention theram :1 Fig; 2; isprovided with a number of pairsofs vertically superposed holes 8,- the;

holes; of each pair being diametrically 1 opposite on, a'iguide collar.9 1f01 the ram. is: a sustaining element comprising a 'rotatable sleeve:l-il' in which are a number of pairsof holes I l. The centresiofgthe-holes ll lieon a double helix-so that eachholehasanotherdiametrically opp'o site to it andlea-chpair of holes isat-a difierent'"$214,440; heighthfromthei others. The guide collarfiyis;

fragmentary viewxof a jack incorporatihgta secondary. sleeve for' fineadjustmentfianged at I2 and the flange rests on the top of the cylinder2.

In use, the jack is raised, 1. e., the ram is lifted, to bring thecrutch I3 (Fig. 1) into engagement with the article to be sustained, thesleeve I is turned to bring two of its holes into register with a pairof holes 8 and a pin I4 is thrust into the four aligned holes and locksthe ramin the raised position, the ram thrusting downwardly onthe pin ifable to overcome the pressure of the work; ing fluid, the pin thrustingon the collar and the collar thrusting on the cylinder through theflange I2 of the guide collar. I The collar 9 is provided in lieu of apacking gland. To overcome the disadvantage arising,

from the absence of a gland at the top of the cylinder the ram isprovided with a s'a'fetyseal' I5. This seal is located at thereduced'bottomof the ram above the usual cup leather I6, said cupleather being secured to the ram by means of a washer II and a bolt I8whichenters a plug I9 forcedinto the bottom of the ram. V a

The seal comprises a packing ring 28 in the lower annular surface ofwhich is a V-groove; and an expander ring ll of triangularcross sectionbut less in height as regards the Vsection than the groove is deep liesin the groove so 'as to expand the lips of the'groovefirst. The expanderrests on the-upper portion of that part of the surface of a flange 22 onth plug I9 which projects beyond the sides of" the ram whilst a movablecollar 23 with an externalflange 24 at its bottom end rests on the topof the ring 2B.. Above the collar 23 and bearing against the shoulder 25on the ram formed by reducing the latter is a collar 26 like 23 butinverted, the flange 21 of said collar 26 thus being at the-top; andbetween the flanges 21 and 24 is a spring 28 which thrusts the collar 23into contact with. the ring 1M3. The ring in turn thrusts against theexpander and as the expander is held against downwardmovement relativelyto the ring by the flange 22 the lips of the groove in the ring aresplayed and make closecontact with the cylinder and the outer surface ofthe ram, respectively. Liquid which leaks past the leather I6 is able toraise the seal I5 until the collar 23butts against the collar 26.Thereafter :the liquid is trapped until pressure on theleather'is'released whereupon the spring is able to expand to theposition shown and the seal I5 drives the liquid back into the cylinderpast the said leather. Either collar (23, 26) may be considerablyshorter than shown and the other as shown-or longer," Spring-means maybeemployed to expand the cupleather in order'to ensure that the seal I5does not the work of the said leather. I

A seal comprising a groove and expander hav-' ing sections differingfrom a vm'aybe' used. Fig. 2 shows one alternative form. In this casethe do all underside of the ring ZD'has'a groove of half round sect-ionand the expander ring 2| is of corresponding shape, the radius ofcurvature, how-' ever," ofthetop ofthe expanderbeinggreater than that ofthe groove to ensure outward move ment of the groove lips by theexpander.

If the jack be laid onits side orinverted the seal I5 will prevent theflow of liquid to that end of the cylinder at which thecollar 9 islocated.

When the bottom of the ram nearly reaches the top of the cylinder theleather I6 passes a hole 28 in the cylinder and further upward movementof the ram is prevented asthe hole allows the working liquid to escapefrom the cylinder, The liquid is conducted to the hollow of one of themembers 3 by means of a valve and a pipe 30; and in accordance with theinvention the valve 29 is of non-return type so that the liquid cannotflow back into the cylinder and escape past the collar 9 ifthe jack islaid on its side or is inverted.

In Fig. 3 an externally screw-threaded, hollow bush 3| is interposedbetween the flange I2 and the. collar III, the lower part of the bore ofthe said collar being screw-threaded for engagement with the bush. Thusthe collar II] can be raised or lowered to permit of adjustments whichare fractional parts of the vertical distance between any two successiveholes I I.

In Fig. 4 the collar III has holes 32 arranged similarly to the holesII, Figs. 1, 2 and 3, but of elongated form, the major axes of the holeslying on the helices on which the centres of the holes lie. Thus, thecollar permits of finer setting of the jack than is possible with thecollar shown in Figs. 1 and 2 as parts of a pair of elongated I holescan be exactly registered with two holes as,8 by turning the collarthrough an angle less than that lying between the centres of twosuccessive holes. a

What I claim is:

1. On an hydraulic jack comprising a cylinder, 2. ram operative in thecylinder, a ram sustaining element encircling the ram and supportedsolely by the cylinder and freely rotatable with respect to the ram andcylinder, said element having holes along its length at differentdistances from its ends and said ram having holes along its length, anda free pin to be passed through transversely registering holes in thesustaining element and in the ram whereby the ram is :held againstsinking with relation to the cylinder.

2-. On an hydraulic jack comprising a ram in a cylinder, a,freely-rotatable sleeve mounted on said jack in'surrounding relation tosaid rain at the top of the cylinder, said .sleeve having holes indiametrically-opposed pairs along, its length, each pair of holes beingat relatively difierent distances from its ends and said ram havingholesalong its length, and a free pin, said pin being adapted to enter aholein the sleeve and a hole in the ram whereby the ram is held againstsinking with relation to the jack cylinder.

3. On an hydraulic jack according to claim 2, said'sleev e having holesthe centres of which lie on a helix. x

4. On an hydraulic jack according to claim 2, wherein the sleeve isvertically adjustable with respect to "the ram' and wherein the centersor the respective diametrically-opposed pairs of holes lie on helicesand said ram having diametralholes.

5. On an hydraulic jack according to claim 2, said sleeve havingelongated holes/the centres of whic'nlie on a.helix and the major axesof which rise slightly.

6. On an hydraulic jack according to claim 2, said sleeve having ascrew-thread, a screwthreaded bush engaging with said screw-thread onsaid sleeve, said bush being rotatably mounted onthe jack. I

7. In anhydraulic jack according to claim 2, a guide collar arrangedbetween the ram and cylinder and providing a bearing contact for theram, said collar being mounted in the upper end of the cylinder, aflange on said guide collar bearing against the top ofthe cylinder, andsaid fluid from such reservoir under pressure for operating the ram.

9. A construction as defined in claim 2, wherein means are provided forpreventing any leakageof operating fluid from reaching the sleeve.

10. A construction as defined in claim 2, wherein spring operated meansare provided to prevent leakage of operating fluid from reaching thesleeve, and wherein such spring operated means automatically returnssuch leakage for power service on the ram.

JAMES STEWART ROTI-IERY.

